RCgothic

I'm 70% for Scrub/pad abort. If not, I think the booster gets through maxQ and performs its landing in the Gulf. SpaceX have the actual flight portion down I reckon. At stage SEP, I think 80% Starship lights correctly and makes it to the intended trajectory. If it gets that far, I think 80% the ship disintegrates on re-entry. I don't think it's going to get as far as the belly flop and if it does that will be a mission 200% success and SpaceX will be ecstatic. Merged post: Troubleshooting a pressurisation issue on S1. Needs to be resolved before launch.

I think there's another asset in Hawaii already. Not sure if it's already in the air.

Go for prop load! T-0 has slipped 20m. Fuelling has begun: WB57s have a flight endurance of about 6.5h. Minus an hour to and from, that's 4.5h availability over the launch site. And as you mention it can always land in South Texas if it needs to stay up a little bit longer. Should easily cover the entire flight window.

It'll fly above Starbase and the gulf for a while to observe the launch and then return to the runway it took off from. It appears that fuelling of Starship is yet to start, so T-0 looks like it's slipping later into the window.

NASA WB57 observation aircraft is now airborne and en-route to Starbase.

You can think of lift and drag in two functionally equivalent ways. 1) As a pressure difference over the wing area. The force vector produced holds the wing up, but also pulls it back as drag. If air spills around the wing tips, the pressure difference gets reduced so a greater pressure difference is required. At constant airspeed this is acheived by a higher angle of attack, so the ratio of lift to drag changes unfavourably as the lift vector points more aft. 2) As conservation of momentum. If a wing accelerates downward an aircraft's mass of air each second, by conservation of momentum the aircraft is held up against 1g. The wing also drags the air forward, and by conservation of momentum the wing is dragged back, with the ratio depending on angle of attack. Vortices spilling around the wingtips don't contribute to linear momentum change, as circular motion has no overall direction. This is in effect wasted effort as the wing converts its linear momentum into useless angular momentum.

I'm pretty sure S2 also has star trackers for attitude determination. Not sure S1 would need such.

The Falcon booster navigates to pre-set GPS location together with pre-estimated wind conditions. Once it's in the vicinity of the landing zone I believe there's a guidance signal that helps it make the final course corrections, and a landing radar for for judging altitude accurately. So it's a mix of pre-programmed instructions, dynamic adjustment if engine performance and winds aren't as expected, and terminal guidance.

Launch window: (Image quality is better on John Kraus's tweet) Only the evac notice still to go. These are typically issued close to the launch attempt.

FAA Statement

Now being reported by multiple sources: Confirmation of IFT (Integrated Flight Test) launch date by SpaceX:

Brace Brace Launch license issued! We have a go for launch prep!

NOTMAR issued:

We now have road closures and TFR. Still awaiting FTS arm and restacking, and launch license.

Yeah, Terran R with full reusability was the only vehicle I'd rated in the same category as starship. But it looks like it's probably going to be another Falcon clone with similar LEO payload and worse mass fractions. Nobody took 1st stage reuse seriously, and now they're over half a decade behind the curve on that. Now nobody's taking full reuse seriously and it's hard to see how they can catch up unless they do.

Also the AeonVac failure to ignite apparently caused by a vapour bubble on the lox turbine leading to low pressure and the gas generator failing to ignite.

De-stacking for FTS arm. It's good.

https://www.spacex.com/

Looks like someone forgot to disconnect a cable.

Gravity is a field. Setting up a gravity field would take energy at least equivalent to moving every massive object within it from infinity to its position inside the field, because work is energy is force times distance. How much energy this is depends on the size of the field. If the field drops from 1g to ~0 over 10m it could be as little as 12.5J/kg for objects at the 1g level. Less for objects further away, more for any objects below the "deck". For this reason the design would probably need to minimise the mass between the artificial gravity generator and the useful gravity zone. The energy put into establishing the field may be regeneratively recovered when it's disestablished. For comparison 1J isn't a lot. It takes 4200J to heat 1kg of water by 1°C. It needn't take any energy to maintain a gravity field either. Objects at rest within a field aren't having any work done upon them. The system would need to supply the energy for any movement of objects. The only question then is how efficiently your gravity generator can convert electrical power into gravity fields and keep them operating. And as this is mythic tech with no known, this could be anything from next to nothing to "needs energy totalling the mass of a planetoid with equivalent surface gravity".

Yeah, if I'd had to bet on which one of Virgin Orbit or Galactic would survive, I'd have picked Orbit. Now I'm thinking neither.

So Vulcan probably isn't launching H1:

Historically yes, total cost per launch has been king. And it is still possible to win some launches that way (for now). But that's not where launch growth is and danger that way lurks. If Rocket A can launch 20 sats at once for $45m, Rocket B can launch 9 sats at once for $30m, and you have 360 sats to launch, all else being equal you pick Rocket A because you'd only pay $810m for 18 launches instead of $1.2B. And also Rocket A just won 18 launches together instead of negotiating them individually. Megaconstellations are where the growth is. If Neutron can't get into that market, then it will have failed. If Rocket B does some work and gets it's cost down to $20m, then congrats - the cost per kg (or per sat) is now competitive. Otherwise the fact it's cheaper per launch will only win it a fraction of the launches Rocket A gets in future. Now imagine Rocket A can launch for $38m for the same profit margin Rocket B makes at $34m, and Rocket B really can't easily go below $30m and still repay it's creditors. Except Company A is more financially secure than Company B and not beholden to shareholders. It can happily operate at $28m per launch for a while while it puts Company B out of business. This is the situation Rocketlab are in danger of finding themselves in - unable to compete on price per kg or per total launch. Finally, Rocket A2 is on the horizon. Rocket A2 recovers all hardware, only needs maintenance every few flights, is reusable over dozens of flights, and its only major BOM cost is fuel. It can launch 100 sats at once and gets charged out to customers at $25m per flight which is a profit margin of about 1000%. Rocket A2 is the Dreadnaught of rockets, and it makes all other rockets obsolete. Companies B, C, D and so on through Z are all screwed if they're pinning their hopes on their newest offerings *maybe* being competitive with the original Rocket A.